It is known that charcoal may be produced by moving organic material through retorts, or heated anaerobic vessels. For example, Canadian Patent Application No. 2,110,282 relates to a method of treating biomass material wherein the material is carried through a heated casing by an auger which runs the entire length of the heated casing.
Canadian Patent Application No. 2,140,898 discloses an apparatus that allows thermal dimensional changes of metal parts in a retort mechanism which incorporates heating and cooling stages and comprises a retort auger that extends the entire length of the retort.
Canadian Patent No. 2,242,279 discloses an apparatus for continuous charcoal production comprising a heated tubular retort with a screw element extending through the retort. The flight of the screw element is separated into sections by gaps coincident with gas vents penetrating the retort.
Japanese Patent Document 58-501912 discloses a method for manufacturing carbonised briquettes by introducing vegetable matter into a heated retort. The heated retort incorporates a screw to advance material through the retort.
Australian Patent Document 90 50613 discloses an apparatus for use in the production of charcoal comprising a hollow retort shell containing an auger for advancing material through the shell.
A significant problem with prior systems is that organic material often adopts a viscous liquid or semi-solid state at a certain stage during the conversion to charcoal. Tar and creosote are typical examples of such partially converted organic material. These materials are sticky and often form plugs within the retort, often where the retort is initially exposed to heat. Plugs impede the steady feed-through of material and in some instances can completely block the advance of organic material. Removing plugs can be costly, and may require shutting down the system and disrupting otherwise continuous charcoal production. Plugs can also prevent pyrolysis gases from properly venting from retorts. Gas condensers to which pyrolysis gases are vented may also become congested with partially converted organic material.
There is a need for apparatus and methods that reduce or eliminate plug formation and congestion in retort charcoal reactor systems.